The invention relates to a fault recognition circuit for at least two power supply units feeding a user at their output side, the power supply units having a switching transistor, a power transformer, and a rectifier portion with a following filter element.
The trend toward higher power densities and the high availability demands of data processing systems necessarily requires the connection of a plurality of power supply units in parallel. The relationship between costs and availability thus decides whether a system of power supply units connected in parallel be redundantly designed. Since high availability of a system simultaneously means short repair times, it is decisive, among other things, that the power supply unit which is down be immediately recognized after outage.